Endoscope apparatus

ABSTRACT

There is provided an endoscope apparatus which can notify an operator whether or not a forceps elevator is in a reclined state by simple and inexpensive means. The endoscope includes: a forceps elevator which is erectably provided at the distal end part of an operation part that is provided to the insertion part. The forceps elevator has an erecting motion range from a minimum angular position to a maximum angular position. The operation part includes an index which is shielded by the erecting operation member when the forceps elevator is in the minimum angular position, and which is exposed when the forceps elevator is in a position in which the forceps elevator is erected from the minimum angular position.

CROSS-REFERENCE TO RELATED APPLICATIONS

The patent application claims priority under 35 U.S.C. §119 to JapanesePatent Application No. 2014-202579, filed on Sep. 30, 2014. Each of theabove application(s) is hereby expressly incorporated by reference, inits entirety, into the present application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an endoscope apparatus, andspecifically, relates to an endoscope apparatus including an erectingoperation member for erecting a forceps elevator (treatment toolelevator) of a distal end part a traction of an operation wire.

2. Description of the Related Art

In an ultrasonic inspection in an ultrasonic endoscope, tissue samplingand suction by a puncture needle are optionally performed under theultrasonic endoscope.

Moreover, a guide wire and a contrast tube are inserted in a bile ductor the like in duodenoscopy and endoscopic retrogradecholangiopancreatography (ERCP) is performed.

A puncture needle and a guide wire, and so on, are inserted from atreatment tool entry port of an endoscope and led out from a treatmenttool exit port provided in the distal end part of the endoscope througha treatment tool insertion channel.

A forceps elevator is provided to the treatment tool exit port and isdesigned such that the forceps elevator can be moved from a reclinedstate to an erected state by operating an erecting operation member topull an operation wire (see Japanese Patent Application Laid-Open No.5-56912). Thus, the puncture needle or the guide wire, which is led outfrom the treatment tool exit port, becomes able to approach a body wallor a duodenal papilla at a desired angle.

Generally, a forceps elevator is in a reclined state when an insertionpart of an endoscope is inserted into and extracted from a body or whena bending part is bent.

Japanese Patent Application Laid-Open No. 5-56912 discloses that a scaleshowing an erecting angle is provided near an erecting operation memberof an operation part.

Japanese Patent Application Laid-Open No. 2005-287593 discloses that amark is provided to a part of a forceps elevator that is imaged in anobservation image when the forceps elevator is reclined.

SUMMARY OF THE INVENTION

However, Japanese Patent Application Laid-Open No. 5-56912 indicates theerecting angle of the forceps elevator, and it does not actively notifyan operator that the forceps elevator is in a reclined state. Moreover,in Japanese Patent Application Laid-Open No. 5-56912, it issubstantially necessary to provide a position detecting device, andthere is a problem of making an endoscope heavy and causing an increasein costs.

In Japanese Patent Application Laid-Open No. 2005-287593, since the markis provided in the observation image, there is a disadvantage that itbecomes unable to observe the periphery of the mark.

The present invention is made considering such circumstances, and aimsto provide an endoscope apparatus which can notify an operator whetheror not a forceps elevator is in a reclined state by simple andinexpensive means.

To achieve the above-mentioned object, an endoscope according to anaspect of the present invention includes: an insertion part configuredto be inserted into a body; an operation part continuously provided on aproximal end side of the insertion part; a forceps elevator which iserectably provided to a distal end part of the insertion part, has anerecting motion range from a minimum angular position to a maximumangular position, and is configured to guide a treatment tool led outfrom the distal end part; an operation wire whose one end is coupledwith the forceps elevator and which is inserted into the insertion part;and an erecting operation member which is provided to the operationpart, with which another end of the operation wire is coupled, and whichis configured to erect the forceps elevator by pulling the operationwire, wherein the operation part includes an index which is shielded bythe erecting operation member when the forceps elevator is in theminimum angular position, and which is exposed when the forceps elevatoris in a position in which the forceps elevator is erected from theminimum angular position.

In the endoscope apparatus according to the aspect of the presentinvention, it is possible to notify an operator whether the forcepselevator is in the minimum angle position, that is, whether the forcepselevator is in a reclined state, only by providing the index to theoperating unit. This can be easily realized at a low cost.

In the endoscope apparatus according to the aspect of the presentinvention, it is possible to adopt a mode in which, when a state inwhich the treatment tool is not led out from the distal end part isassumed, the erecting operation member has: a first operation range inwhich the operation wire is pulled within the erecting motion range ofthe forceps elevator; and a second operation range in which theoperation wire is further pulled when the erecting operation member isgreatly pulled beyond the first operation range.

According to this mode, in a state in which the treatment tool is notled out from the distal end part, the endoscope apparatus has the secondoperation range in which the operation wire can be further pulled,compared to the first operation range which is sufficient to erect theforceps elevator from the minimum angular position to the maximumangular position. Thus, it is possible to erect the forceps elevator tothe maximum angular position by performing an operation in the secondoperation range even when the forceps elevator cannot be erected to themaximum erecting angle only by an operation in the first operationrange, at the time of erecting a treatment tool having large bendingstiffness.

In the endoscope apparatus according to the aspect of the presentinvention, it is possible to adopt a mode in which the operating partincludes a locking mechanism configured to lock a movement of theerecting operation member when the erecting operation member is operatedinto the second operation range.

According to this mode, even when a treatment tool having large bendingstiffness is led out from the distal end part, the forceps elevator canbe erected to the maximum erecting angle by operating the erectingoperation member in the second operation range. And, at this time, themovement of the erecting operation member can be locked by the lockingmechanism. Therefore, it is possible to mitigate a load that an operatorhas to keep applying the operating force toward the erecting side to theerecting operation member in order to hold the erecting state of theforceps elevator, and the state of the forceps elevator is alsostabilized.

In the endoscope apparatus according to the aspect of the presentinvention, it is possible to adopt a mode in which there are provided: afixed part provided in the operation part; and a movable part which isprovided integrally with the erecting operation member and is movablerelative to the fixed part, wherein the locking mechanism includes: alocking pin which is provided to one of the fixed part and the movablepart; and a locking projection which is provided to another one of thefixed part and the movable part, and supported by an elastic supportmember that is elastically deformable, and the locking mechanism locksmovement of the erecting operation member by engagement between thelocking pin and the locking projection when the erecting operationmember is operated into the second operation range.

According to this mode, the locking mechanism is realized with a simpleconfiguration.

In the endoscope apparatus according to the aspect of the presentinvention, it is possible to adopt a mode in which a bending operationknob which is rotatably arranged to the operation part and is configuredto perform a bending operation of a bending part provided on a distalend side of the insertion part is further included, and the erectingoperation member is rotatably arranged on a same axis as a rotation axisof the bending operation knob.

According to the present invention, it is possible to notify an operatorwhether or not a forceps elevator is in a reclined state by simple andinexpensive means.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an ultrasonic endoscope according to anembodiment of an endoscope apparatus to which the present invention isapplied;

FIG. 2 is an expanded perspective view illustrating a distal end part;

FIG. 3 is an expanded side view illustrating an operation part;

FIG. 4 is an expanded bottom view illustrating the operation part;

FIG. 5 is a configuration diagram simply illustrating the entireconfiguration of a forceps elevator drive mechanism;

FIG. 6 is a configuration diagram simply illustrating a powertransmission mechanism in a distal end part;

FIG. 7 is a configuration diagram simply illustrating a powertransmission mechanism in an operation part;

FIG. 8 is an expanded bottom view illustrating the operation part;

FIG. 9 is a side view illustrating the entire forceps elevator;

FIG. 10 is a relationship diagram illustrating the relationship betweenthe operation range of an erecting operation lever and the erectingmotion range of the forceps elevator in a state where a treatment toolis not led out from a distal end part (treatment tool exit part);

FIG. 11 is a diagram illustrating a state when a puncture needle is ledout from a distal end part (treatment tool exit part) and the cellulartissue is collected;

FIG. 12 is a relationship diagram illustrating a relationship between anoperation range of the erecting operation lever and an erecting motionrange of the forceps elevator in a state where the treatment tool havinglarge bending stiffness is led out from a distal end part (treatmenttool exit part);

FIG. 13 is an expanded diagram illustrating indices provided in a partwhich is arranged opposite to the erecting operation lever in the lowersurface of the operation part;

FIG. 14 is a diagram illustrating another mode of indices;

FIG. 15 is a diagram illustrating a locking mechanism provided in atransmission mechanism in the operation part;

FIG. 16 is an expanded perspective view illustrating the lockingmechanism provided in the transmission mechanism in an operation part;

FIG. 17 is a diagram simply illustrating configurations of a fixed partand movable part of the locking mechanism along the circumferentialdirection when they are developed in a plane, and is a diagramillustrating a relationship with an angular position of the erectingoperation lever;

FIG. 18 is a diagram illustrating a specific example about a position ofa locking pin, and is a diagram simply illustrating configurations of afixed part and movable part of a locking mechanism along thecircumferential direction when they are developed in a plane;

FIG. 19 is a diagram illustrating a specific example about the positionof a locking pin, and is a diagram simply illustrating configurations ofthe fixed part and the movable part of the locking mechanism along thecircumferential direction when they are developed in a plane;

FIG. 20 is a diagram illustrating a modified example of the movable partof the locking mechanism;

FIG. 21 is a diagram illustrating a modified example of a fixed part ofthe locking mechanism, and is a diagram where multiple locking pins arediscretely disposed;

FIG. 22 is a diagram illustrating a modified example of a fixed part ofthe locking mechanism, and is a diagram where multiple locking pins arecontinuously disposed;

FIG. 23 is a perspective view of a latch board forming a locking pin inFIG. 22;

FIG. 24 is a diagram illustrating a modified example of a fixed part ofthe locking mechanism, and is a diagram where a friction plate isdisposed instead of a locking pin;

FIG. 25 is an image diagram illustrating a mechanism that makes amovable plate of the locking mechanism approach or move away from astationary plate;

FIG. 26 is an image diagram illustrating the mechanism that makes themovable plate of the locking mechanism approach or move away from thestationary plate;

FIG. 27 is an image diagram illustrating the mechanism that makes themovable plate of the locking mechanism approach or move away from thestationary plate;

FIG. 28 is a diagram illustrating the shape of a locking projection ofthe movable part in a case where the amount of force required to themovement to the reclining side of the movable part in the lockingmechanism is made greater than the amount of force required to themovement on the erecting side;

FIG. 29 is a diagram illustrating the shape of a locking projection of amovable part in a case where the amount of force required to themovement to the reclining side of the movable part in the lockingmechanism is made greater than the amount of force required to themovement on the erecting side;

FIG. 30 is a diagram illustrating the configuration of a locking pin ofa movable part in a case where the amount of force required to themovement to the reclining side of the movable part in the lockingmechanism is made greater than the amount of force required to themovement on the erecting side;

FIG. 31 is a diagram illustrating a state where the locking pin of thefixed part in FIG. 30 rotates;

FIG. 32 is a diagram illustrating a state where the operation part isheld with a general method and the erecting operation lever is operatedwhen an endoscope is operated; and

FIG. 33 is a diagram illustrating a state where the operation part isheld with a general method and the erecting operation lever is operatedwhen the endoscope is operated.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In the following, preferable embodiments of the present invention aredescribed in detail according to the accompanying drawings.

FIG. 1 is a schematic diagram of an ultrasonic endoscope 1 that is anembodiment of an endoscope apparatus to which the present invention isapplied.

The ultrasonic endoscope 1 (which is simply called an endoscope 1 below)is includes: an insertion part 10 which is to be inserted in the insideof a subject's body; an operation part 12 which is continuously providedon the proximal end side of the insertion part 10 and which is to beholed by an operator to perform various operations; and a universal cord14 which is continuously provided in the operation part 12 and connectsthe endoscope 1 with system configuration apparatuses which areconstituting an endoscope system such as an unillustrated processorapparatus and a light source apparatus.

The insertion part 10 is formed into a long shape with a narrow diameteras a whole and is configured by continuously arranging a flexible part30 having flexibility, a bending part 32 which is bendable by anoperation of the operation part 12, and a distal end part 34 in which animaging apparatus, an ultrasonic transducer (electromagnetic acoustictransducer) and so on are disposed, in this order from the proximal endside to the distal end side.

Various operating members to be operated by an operator are provided inthe operation part 12, and, as described later, a right-and-left angleknob 70 and an up-and-down angle knob 72 which are bending operationknobs, an erecting operation lever 74 which is an erecting operationmember, an air and water supply button 80 and a suction button 82, andso on, are provided.

Moreover, the operation part 12 a includes treatment tool entry port 24through which a treatment tool is inserted into a treatment toolinsertion path (treatment tool insertion channel) which passes throughthe insertion part 10.

The universal cord 14 internally includes an electric cable, a lightguide and a fluid tube. A connector is provided in an unillustrated endpart of this universal cord 14. The connector is connected with thepredetermined system configuration apparatus forming the endoscopesystem such as the processor apparatus and the light source apparatus,and thus, the power, a control signal, illumination light andliquid/gas, and so on, which are necessary for the operation of theendoscope 1, are supplied from the system configuration apparatus to theendoscope 1. Moreover, observation image data acquired by the imagingapparatus of the distal end part 34 and ultrasonic image data acquiredby the ultrasonic transducer are transmitted from the endoscope 1 to thesystem configuration apparatuses. Here, the observation image and theendoscope image, which are transmitted to the system configurationapparatuses, are displayed on a monitor.

FIG. 2 is an expanded perspective view illustrating the distal end part34. As illustrated in the figure, the distal end part 34 includes a basepart 40 disposed on the proximal end side and an extension part 42 whichextends from the base part 40 provided on the distal end side.

A convex-type ultrasonic transducer 50 in which many ultrasonicvibrators that transmit and receive ultrasonic waves are disposed alongan arc-shaped ultrasonic wave transmission and reception surface isdisposed in the extension part 42. By this means, an ultrasound image(tomographic image) in a scanning surface parallel to the axis of theinsertion part 10 is acquired by the ultrasonic transducer 50 and dataof the image are transmitted to the system configuration apparatusesconnected with the universal cord 14 through a signal cable insertedinside the insertion part 10, the operation part 12 and the universalcord 14.

In the base part 40, an observation window 44, an air and water supplynozzle 48 and an illumination window 46L are provided in a left sideslope 41L facing obliquely upward on the distal end side, and anillumination window 46R is provided in a right side slope 41R directedobliquely upward on the distal end side. The treatment tool exit part 58is provided in the central part between the left side slope 41L and theright side slope 41R.

An imaging apparatus in which an image formation optical system and asolid imaging element are integrally assembled is disposed inside thebase part 40 that is the proximal end side of the observation window 44.By this means, light from a site to be observed that is the visual fieldrange of an imaging unit is collected from the observation window 44, anoptical image of the site to be observed is formed by the imageformation optical system, and the optical image is converted into anelectrical signal by the solid imaging element. Further, the observationimage data converted into the electrical signal is transmitted to thesystem configuration apparatuses connected with the universal cord 14through the signal cable inserted inside the insertion part 10, theoperation part 12 and the universal cord 14.

A light emitting unit is disposed inside the base part 40 that is theproximal end side of each of the illumination windows 46R and 46L.Illumination light is led out from the system configuration apparatusesconnected with the universal cord 14 through the light guide insertedinside the insertion part 10, the operation part 12 and the universalcord 14 to the light emitting unit. The illumination light is emittedfrom the light emitting unit through the illumination windows 46R and46L to irradiate the site to be observed.

An air and water supply nozzle 48 is connected with the systemconfiguration apparatuses connected with the universal cord 14 through afluid tube inserted inside the insertion part 10, the operation part 12and the universal cord 14. The gas or water supplied from the systemconfiguration apparatus is jetted from the air and water supply nozzle48 toward the observation window 44 and the washing or the like of theobservation window 44 is performed.

The treatment tool exit part 58 has a concave treatment tool erectingspace 62, and a treatment tool exit port 64 is disposed on the proximalend side of the treatment tool erecting space 62.

The treatment tool exit port 64 is coupled with the treatment tool entryport 24 of the operation part 12 (see FIG. 1) through the treatment toolinsertion path (treatment tool insertion channel) passing through theinsertion part 10, and a treatment tool inserted from the treatment toolentry port 24 is led out from the treatment tool exit port 64 to thetreatment tool erecting space 62.

Moreover, in the treatment tool erecting space 62, a forceps elevator 60is disposed on the distal end side with respect to (closer to the distalend than) the treatment tool exit port 64.

The forceps elevator 60 has a concave guide surface 60 a bended upwardfrom the proximal end side to the distal end side on the upper surfaceside, and the treatment tool led out from the treatment tool exit port64 abuts on the guide surface 60 a of the forceps elevator 60 and bendsupward. By this means, the treatment tool led out from the treatmenttool exit part 58 of the distal end part 34, that is, the treatment toolled out from an opening part 66 of the treatment tool erecting space 62is protrusively disposed (disposed so as to protrude) along an obliqueupward direction from the proximal end side to the distal end side withrespect to the central axis (the longitudinal axis of the insertion part10) that passes through the center of the distal end part 34, by theforceps elevator 60.

FIGS. 3 and 4 are an expanded side and an expanded bottom viewillustrating the operation part 12.

As illustrated in these figures, the operation part 12 is covered with acasing 13 which is an operation part body that defines the inside andoutside of the operation part 12. In a right side surface 13R of theoperation part 12 formed by the casing 13, a right-and-left angle knob70, an up-and-down angle knob 72, an erecting operation lever 74, aright-and-left lock knob 76 and an up-and-down lock lever 78, and so on,are provided.

Here, normally, when operating the endoscope 1, as illustrated in FIG.32, an operator (operating person) holds the operation part 12 by theleft hand while turning the distal end side of the operation part 12(the side of the insertion part 10) to the bottom and turning theproximal end side which is the opposite side to the top, and then holdsthe operation part 12 such that the palm of the left hand faces the sideof the left side surface 13L which is the side opposite to the rightside surface 13R in which the right-and-left angle knob 70 or the likeis disposed, an upper surface 13U is caught with other fingers than thethumb and a lower surface 13D is caught with the thumb. In this case,the upper surface 13U of the operation part 12 faces the front side, anda lower surface 13D of the operation part 12 faces the rear side(operator side), as seen from the operator.

The right-and-left angle knob 70, the up-and-down angle knob 72, theerecting operation lever 74, the right-and-left lock knob 76 and theup-and-down lock lever 78 of the operation part 12 are provided so as tobe rotatable around an axis which is substantially orthogonal to theright side surface 13R. When the right-and-left angle knob 70 and theup-and-down angle knob 72 are rotated, the bending part 32 is bended inthe right-and-left direction and the up-and-down direction. When theright-and-left lock knob 76 and the up-and-down lock lever 78 arerotated, the rotational positions of the right-and-left angle knob 70and the up-and-down angle knob 72 are locked or the lock is released.

When the erecting operation lever 74 is rotated, it works in directionsin which the forceps elevator 60 in the distal end part 34 erects orreclines, and the angular position (erecting angle) of the forcepselevator 60 is varied, as described later in detail. By this means, thelead-out direction (lead-out angle) of the treatment tool led out fromthe distal end part 34 (the treatment tool exit part 58) is varied.

Here, the erecting operation lever 74 is operated by the thumb asillustrated in FIGS. 32 and 33.

Moreover, the air and water supply button 80, the suction button 82, andso on, are provided in the upper surface 13U of the operation part 12 asillustrated in FIG. 3. The jet of gas or water from the air and watersupply nozzle 48 in the distal end part 34 can be turned on or off byoperating the air and water supply button 80. Suction from the treatmenttool exit part 58 can be turned on or off through a suction channelcoupled with a treatment tool insertion path by operating the suctionbutton 82.

Next, a forceps elevator drive mechanism which erects or reclines theforceps elevator 60 of the distal end part 34 by the operation of theerecting operation lever 74 of the operation part 12 is described. Here,in this specification, the erecting motion and reclining motion of theforceps elevator 60 are collectively called erecting motion.

FIG. 5 is a configuration diagram simply illustrating the wholeconfiguration of the forceps elevator drive mechanism.

As illustrated in the figure, in the operation part 12, one end of acrank member 92 is rotatably coupled with the erecting operation lever74 through a below-mentioned operation-part power transmission mechanism90 disposed in the operation part 12. A slide 96 which is supported by aslide guide 94 movably forward and backward is coupled with the otherend of the crank member 92 so as to be rotatable with respect to thecrank member 92. By this means, the slider 96 moves forward and backwardby the operation (movement) of the erecting operation lever 74.

The proximal end of an operation wire 98 is fixed to the slider 96. Theoperation wire 98 is inserted from the inside of the operation part 12and extends through the inside of the insertion part 10, up to thedistal end part 34. Here, the operation wire 98 is disposed inside theinsertion part 10 to pass through a wire guide tube 99 such as a contactcoil so as to be able to move forward and backward.

Further, in the distal end part 34, the forceps elevator 60 is coupledwith the distal end of the operation wire 98 through a distal-end-partpower transmission mechanism 100 described below. The proximal end sideof the forceps elevator 60 is supported to be rotatable with respect tothe distal end part 34.

By this means, when the operation wire 98 moves forward and backward bythe forward and backward movement of the slider 96, the distal end sideof the forceps elevator 60 is rotated around the proximal end side toerect the forceps elevator 60.

As mentioned above, it is configured such that the power applied to theerecting operation lever 74 by the operation of an operator istransmitted to the forceps elevator 60 through the operation-part powertransmission mechanism 90, the crank member 92, the operation wire 98and the distal-end-part power transmission mechanism 100, so as to allowthe forceps elevator 60 to be erected.

Next, an embodiment of the distal-end-part power transmission mechanism100 in FIG. 5 is described. FIG. 6 is a configuration diagram simplyillustrating the distal-end-part power transmission mechanism 100. Inthe distal end part 34, a lever housing body 120 in FIG. 6, which formsa part of a side surface on the right side, is arranged in a positionfacing a wall surface on the right side of the treatment tool erectingspace 62 of the treatment tool exit part 58 illustrated in FIG. 2.

The lever housing body 120 has a wall part forming the wall surface onthe right side of the treatment tool erecting space 62, a rotating shaftmember 122 is rotatably supported while penetrating the wall part. Oneend part of the rotating shaft member 122 projects to the treatment toolerecting space 62 and the other end part projects to a lever housingspace part 124 formed inside the lever housing body 120.

Further, the end part on the proximal end side of the forceps elevator60 is fixed to the end part that projects to the treatment tool erectingspace 62 of the rotating shaft member 122 (see FIG. 5). On the otherhand, an end part on the proximal end side of a erecting lever 126housed in the lever housing space part 124 is fixed to the end part thatprojects to the lever housing space part 124 of the rotating shaftmember 122. The tip end of the operation wire 98 is rotatably coupledwith an end part on the distal end side of the erecting lever 126(through a connection pin rotatable with respect to the erecting lever126) (see FIG. 5).

By this means, when the operation wire 98 moves forward and backward bythe operation of the erecting operation lever 74 of the operation part12, the erecting lever 126 rotates around an axis 122 x passing throughthe center of the rotating shaft member 122 together with the rotatingshaft member 122. Further, the forceps elevator 60 rotates around theaxis 122 x together with the rotating shaft member 122 by the rotationof the rotating shaft member 122 and is subjected to erecting motion.

Here, in FIG. 6, the front end of the wire guide tube 99 which isillustrated in FIG. 5 and through which the operation wire 98 isinserted is fixed to the proximal end side of the lever housing body120. Moreover, a tube member 130 in the figure is a member forming atreatment tool insertion channel, and it is connected so as tocommunicate with the treatment tool entry port 24 (see FIG. 2).

Moreover, the distal-end-part power transmission mechanism 100, whichtransmits the power by the forward and backward movement of theoperation wire 98 as a power to erect the forceps elevator 60, is notlimited to the configuration of the above-mentioned embodiment, and anarbitrary configuration can be adopted. For example, a configuration inwhich the tip of the operation wire 98 is directly coupled with theforceps elevator 60 may be possible, or a configuration in which theoperation wire 98 is indirectly coupled with the forceps elevator 60 bya configuration different from the above-mentioned embodiment may bepossible.

Next, an embodiment of the operation-part power transmission mechanism90 in FIG. 5 is described. FIG. 7 is a configuration diagram simplyillustrating the operation-part power transmission mechanism 90. Asillustrated in the figure, a through hole 13 a which communicates theinside and outside of the casing 13 is formed in a part in which theright side surface 13R (see FIGS. 3 and 4) of the casing 13 that is anoperation part main body of the operation part 12. In the through hole13 a, a columnar main shaft 150 and a cylindrical fixing shaft 152 (seeFIG. 5) which extend from the inside to the outside of the casing 13 andwhich are substantially orthogonal to the right side surface 13R areprovided on the same axis along an axis 150 x.

Regarding these main shaft 150 and fixing shaft 152, one end parts (endparts on the proximal end side) are fixed to a support part 13 b whichis a part of the casing 13 or a part of a member fixed to the casing 13,in the inside of the casing 13.

Here, there is a space between the outer peripheral surface of the mainshaft 150 and the inner peripheral surface of the fixing shaft 152, andan unillustrated power transmission mechanism is disposed between them,where the power transmission mechanism transmits the power by respectiverotation operations of the right-and-left angle knob 70 and theup-and-down angle knob 72 which are illustrated in FIGS. 3 and 4, to aright-and-left operation wire which bends the bending part 32 in theright and left direction and an up-and-down operation wire which bendsthe bending part 32 in the upper and lower direction respectively.

For example, the fixing shaft 152 includes a large diameter part 152 aand a small diameter part 152 b, in which the diameter on the proximalend side is expanded more than the distal end side. On the innerperipheral surface side of the large diameter part 152 a, two pulleys,which rotate around the main shaft 150 and wind and pull each of theright-and-left operation wire and the up-and-down operation wire, aredisposed. Further, respective cylindrical double rotation shafts arecoupled with those respective pulleys, and those rotation shafts areinserted between the outer peripheral surface of the main shaft 150 andthe inner peripheral surface of the fixing shaft 152, and coupled withthe right-and-left angle knob 70 and the up-and-down angle knob 72respectively. Here, the right-and-left angle knob 70 and the up-and-downangle knob 72 are supported so as to be rotatable around the axis 150 x.

In the outer peripheral part of the small diameter part 152 b of thefixing shaft 152, a cylindrical rotating drum 154 (see FIG. 5) issupported so as to rotatable around the fixing shaft 152 (around theaxis 150 x). An annular frame member 160 fixed to the casing 13 isdisposed between the outer peripheral surface of the rotating drum 154and the inner peripheral surface of the through hole 13 a of the casing13. An O-ring (O-ring) which is mounted to the inner peripheral surfaceand outer peripheral surface of the frame member 160 presses against theouter peripheral surface of the rotating drum 154 and the innerperipheral surface of the through hole 13 a, and the space between therotating drum 154 and the casing 13 is sealed. Here, the frame member160 may be a part which is formed integrally with the casing 13 as apart of the casing 13.

A coupling member 156 includes an annular fixed part 156 a and an armpart 156 b (see FIG. 5) which extends from a part of the fixed part 156a in the radial direction is fixed to one end part (an end part on thedistal end side) of this rotating drum 154 by a screw, and so on. Afinger hook part 158 (see FIG. 5) is fixed to the distal end part of thearm part 156 b of the coupling member 156. The erecting operation lever74 is formed with the arm part 156 b and the finger hook part 158. Bythis means, the erecting operation lever 74 is disposed so as to berotatable around the axis 150 x in a position along the right sidesurface 13R outside the operation part 12.

Here, the finger hook part 158 of the erecting operation lever 74 has abent shape and is disposed so as to extend from a position facing theright side surface 13R of the operation part 12 (casing 13) to aposition facing the lower surface 13D.

On the other hand, a convex part 155 that projects in the radialdirection is provided in the other end part (the end part on theproximal end side) of the rotating drum 154, and one end of theabove-mentioned crank member 92 (see FIG. 5) is coupled with the convexpart 155 so as to be rotatable.

By this means, when the erecting operation lever 74 rotated around theaxis 150 x, an end part of the crank member 92 rotates around the axis150 x together with the rotating drum 154. The slider 96 in FIG. 5 movesforward and backward by the rotation of the end part of this crankmember 92, and the forceps elevator 60 is erected and reclined throughthe operation wire 98 and the distal-end-part power transmissionmechanism 100.

Here, a mechanism that transmits the power applied to the erectingoperation lever 74 to the operation wire 98 is not necessarily be formedwith the operation-part power transmission mechanism 90 and the crankmember 92, and so on, in the present embodiment. Moreover, the erectingoperation lever 74 of the present embodiment is rotatably disposed onthe same axis as the right-and-left angle knob 70 and the up-and-downangle knob 72 and performs rotation movement, but it may be a mechanismwhich includes the erecting operation lever 74 so as to be freelymovable straight and transmits the power of the straight movement to theoperation wire 98.

Next, the relationship between an operation range of the erectingoperation lever 74 and an erecting motion range of the forceps elevator60 is described.

As illustrated in FIGS. 5 and 7, a cylindrical restriction drum 162fixed to the fixing shaft 152 is disposed inside the rotating drum 154,and a stopper member 164 that projects from the outer peripheral surfaceis fixed to the restriction drum 162. This stopper member 164 isinserted and disposed in a long groove 166 formed along thecircumferential direction in a partial range of the peripheral wall partof the rotating drum 154.

By this means, a rotation angle range in which the rotating drum 154 isrotatable around the axis 150 x is restricted to a rotation angle rangefrom a rotation angle when one end part 166 a (see FIG. 5) of the longgroove 166 abuts on the stopper member 164 to a rotation angle when theother end part 166 b (see FIG. 5) abuts on the stopper member 164.

Further, a rotation angle range in which the erecting operation lever 74can be subjected to a rotation operation, that is, an operation range inwhich the erecting operation lever 74 can be operated is also restrictedto the rotation angle range in which the rotating drum 154 is rotatable.

Here, the position of the erecting operation lever 74 when the erectingoperation lever 74 moves to a position at a rotation angle θ1 around theaxis 150 x is expressed as an angular position θ1. Moreover, when therotation angle range in which the erecting operation lever 74 isrotatable, that is, the operation range in which it can be operated, isassumed as the entire operation range, the angular position θ1 of theerecting operation lever 74 when the end part 166 a of the rotating drum154 abuts on the stopper member 164 is expressed by θ1min as a minimumangular position of the entire operation range, and the angular positionθ1 of the erecting operation lever 74 when the end part 166 b of therotating drum 154 abuts on the stopper member 164 is expressed by θ1max(>θ1min) as a maximum angular position of the entire operation range.

At this time, like the enlarged view in FIG. 8 illustrating theoperation part 12 from the lower surface 13D in the same way as FIG. 4,the erecting operation lever 74 (finger hook part 158) is in a proximalend position on the most proximal end side in the entire operation rangewhen the angular position θ1 is the minimum angular position θ1min. And,the erecting operation lever 74 is in a distal end position on the mostdistal end side in the entire operation range when the angular positionθ1 is the maximum angular position θ1max. The erecting operation lever74 moves within a range from the proximal end position to the distal endposition.

Moreover, the operation wire 98 moves forward to the most distal endside when the erecting operation lever 74 is in the proximal endposition (minimum angular position θ1min) in the entire operation range,that is, when the end part 166 a of the long groove 166 of the rotatingdrum 154 abuts on the stopper member 164 in FIG. 5, and the operationwire 98 moves backward to the most proximal end side when the erectingoperation lever 74 is in the distal end position (maximum angularposition θ1max) in the entire operation range, that is, when the endpart 166 b of the long groove 166 of the rotating drum 154 abuts on thestopper member 164 in FIG. 5.

Therefore, the operation wire 98 can be moved backward to the proximalend side by moving the erecting operation lever 74 from the proximal endposition to the distal end position in the entire operation range toincrease the angular position θ1 of the erecting operation lever 74.

Here, the operation range of the erecting operation lever 74 may berestricted by any device in the operation part 12, and it is not limitedto restriction by making the stopper member 164 abut on the long groove166 of the rotating drum 154 like the present embodiment. For example,it is also possible to adopt a mode in which the operation range of theerecting operation lever 74 is directly restricted by a stopper memberwhich abuts on the erecting operation lever 74, and so on. Moreover, itis also possible to adopt a mode in which the operation range of theerecting operation lever 74 is restricted by restricting the motionrange of an arbitrary member that moves in interlock with the erectingoperation lever 74 in the operation-part power transmission mechanism 90of an arbitrary mode.

On the other hand, in FIG. 6, the erecting lever 126 coupled with theforceps elevator 60 through the rotating shaft member 122 rotates aroundthe axis 122 x that pass through the center of the rotating shaft member122. A rotation angle range in which the erecting lever 126 is rotatablearound the axis 122 x is restricted to a rotation angle range from arotation angle when the erecting lever 126 abuts on a wall surface 124 aon the distal end side on which the lever housing space part 124 of thelever housing body 120 is defined to a rotation angle when the erectinglever 126 abuts on a wall surface 124 b on the proximal end side onwhich the lever housing space part 124 is defined.

By this means, the rotation angle range in which the forceps elevator 60is rotatable, that is, the erecting motion range of the forceps elevator60 is restricted to the rotation angle range in which the erecting lever126 is rotatable.

Here, the position of the forceps elevator 60 when the forceps elevator60 is set to a position at a rotation angle θ2 around the axis 122 x isexpressed as an angular position θ2. Moreover, if the rotation anglerange in which the forceps elevator 60 is rotatable, that is, theerecting motion range in which the forceps elevator 60 can be erectedand reclined is assumed as an erecting motion range, the angularposition θ2 of the forceps elevator 60 when the erecting lever 126 abutson the wall surface 124 a of the lever housing space part 124 isexpressed by θ2min as a minimum angular position in the erecting motionrange, and the angular position θ2 of the forceps elevator 60 when theerecting lever 126 abuts on the wall surface 124 b of the lever housingspace part 124 is expressed by θ2max (>θ2min) as a maximum angularposition in the erecting motion range.

At this time, as illustrated in FIG. 9 illustrating the whole of theforceps elevator 60 from the side surface side, when the angularposition θ2 is the minimum angular position θ2min, the forceps elevator60 is in a maximum reclining position in which the forceps elevator 60is reclined most in the erecting motion range. When the angular positionθ2 is the maximum angular position θ2max, the forceps elevator 60 is ina maximum erecting position in which the forceps elevator 60 is erectedmost in the erecting motion range. The forceps elevator 60 performs theerecting motion within a range from the maximum reclining position tothe maximum erecting position.

Moreover, when the operation wire 98 moves forward to the distal endside, since the erecting lever 126 rotates in a direction in which theerecting lever 126 abuts on the wall surface 124 a on the distal endside of the lever housing space part 124, the forceps elevator 60rotates in a reclining direction and the angular position θ2 of theforceps elevator 60 becomes small. When the operation wire 98 movesbackward to the proximal end side, since the erecting lever 126 rotatesin a direction in which it abuts on the wall surface 124 b on theproximal end side of the lever housing space part 124, the forcepselevator 60 rotates in the erecting direction and the angular positionθ2 of the forceps elevator 60 becomes large.

Therefore, when the erecting operation lever 74 of the operation part 12is operated from the proximal end position to the distal end position inthe entire operation range to make the angular position θ1 of theerecting operation lever 74 large, the operation wire 98 moves backwardto the proximal end side, the forceps elevator 60 of the distal end part34 performs erecting motion in the erecting direction, and the angularposition θ2 of erecting motion becomes large.

Here, the erecting motion range of the forceps elevator 60 may berestricted by any device in the distal end part 34, and it is notlimited to the restriction of the motion range of the erecting lever 126like the present embodiment. For example, it is also possible to adopt amode in which the erecting motion range of the forceps elevator 60 isdirectly restricted by a stopper member which abuts on the forcepselevator 60, and so on. Moreover, it is also possible to adopt a mode inwhich the erecting motion range of the forceps elevator 60 is restrictedby restricting the motion range of an arbitrary member which moves ininterlock with the forceps elevator 60 in the distal-end-part powertransmission mechanism 100 in an arbitrary mode.

Subsequently, FIG. 10 illustrates a relationship diagram between theoperation range of the erecting operation lever 74 and the erectingmotion range of the forceps elevator 60 in a state where a treatmenttool is not led out from the distal end part 34 (treatment tool exitpart 58). The relationship between the operation range of the erectingoperation lever 74 and the erecting motion range of the forceps elevator60 is determined by the size of each of the operation range of theerecting operation lever 74 and the erecting motion range of the forcepselevator 60, the length of the operation wire 98, and so on. In thepresent embodiment, and these values are set so as to establish therelationship as illustrated in FIG. 10.

As shown in FIG. 10, in a case where the angular position θ1 of theerecting operation lever 74 is the minimum angular position θ1min in theentire operation range, the angular position θ2 of the forceps elevator60 becomes in the minimum angular position θ2min in the erecting motionrange. That is, in a case where the erecting operation lever 74 is inthe proximal end position in the entire operation range, the forcepselevator 60 becomes in a maximum reclining position in which the forcepselevator 60 is reclined most.

Then, when the erecting operation lever 74 is operated in a direction tomake the forceps elevator 60 is erected to make the angular position θ1of the erecting operation lever 74 gradually larger, the forcepselevator 60 is gradually erected in response to that operation, and theangular position θ2 gradually becomes larger too. However, it may adopta configuration in which no change is caused in the angular position θ2of the forceps elevator 60 in a range in which the angular position θ1of the erecting operation lever 74 changes by a predetermined angle fromthe minimum angular position θ1min. For example, when a slight play isprovided for the erecting lever 126, the angular position θ2 of theforceps elevator 60 substantially becomes the minimum angular positionθ2min in an angular position in which the angular position θ1 of theerecting operation lever 74 is larger than θ1min.

Here, in the operation direction (movement direction) of the erectingoperation lever 74, it is assumed that a direction to erect the forcepselevator 60 is referred to as the erecting side and a direction torecline the forceps elevator 60 is referred to as the reclining side.

Subsequently, when the angular position θ1 of the erecting operationlever 74 moves to predetermined angular position θ1 a which is smallerthan the maximum angular position θ1max in the entire operation range,the angular position θ2 of the forceps elevator 60 becomes the maximumangular position θ2max in the erecting motion range.

According to this, in a state where the treatment tool is not led outfrom the treatment tool exit part 58, the erecting operation lever 74has the first operation range in which the operation wire 98 is pulledwithin the erecting motion range of the forceps elevator 60, from theminimum angular position θ1min to the angular position θ1 a. Then, whenthe erecting operation lever 74 is greatly operated toward the erectingside beyond the first operation range, the erecting operation lever 74has the second operation range in which the operation wire 98 is pulledmore, from the angular position θ1 a to the maximum angular positionθ1max. When the erecting operation lever 74 is operated within thesecond operation range, the forceps elevator 60 is maintained in themaximum angular position θ2max.

Thus, when the erecting operation lever 74 has the second operationrange, even in a case where the bending stiffness of the tool treatmentled out from the distal end part 34 through a treatment tool insertionchannel is large (in a case where the treatment tool is difficult tobend), it is possible to erect the forceps elevator 60 up to the maximumangular position θ2max by greatly operating the erecting operation lever74 toward the erecting side beyond the first operation range andoperating the erecting operation lever 74 in the second operation range.

For example, in a case where the cellular tissue is collected from atarget site in a subject's body, like FIG. 11, the ultrasonic wavetransmitting and receiving surface of the ultrasonic transducer 50 ofthe distal end part 34 is made to abut on or become close to a wallsurface S (body wall) near the target site T, and the position of thetarget site T is confirmed by an ultrasonic image acquired by theultrasonic transducer 50. Further, a puncture needle 180 (organizationsampling device) as a treatment tool is inserted into the treatment toolinsertion channel and led out from the treatment tool exit part 58 ofthe distal end part 34. Here, for example, the puncture needle 180 isformed with a cylindrical sheath member 182 and a needle tube 184inserted and disposed in the sheath member 182. When the puncture needle180 is led out from the treatment tool exit part 58, the needle tube 184is housed inside the sheath member 182.

Subsequently, the angular position θ2 of the forceps elevator 60 isadjusted by the operation of the erecting operation lever 74, to adjustthe lead-out direction (lead-out angle) of the puncture needle 180 fromthe treatment tool exit part 58 so that the puncture needle 180 isdirected in the direction of target site T. Further, the distal end ofthe needle tube 184 is led out from the sheath member 182 by theoperation of the operation part for the puncture needle 180 and thefront end the needle tube 184 is inserted from the wall surface S to thetarget site T. By this means, it is possible to take the cellular tissueof the target site T into the distal end of the needle tube 184. Afterextracting the puncture needle 180 from the treatment tool insertionchannel, it is possible to collect the cellular tissue of the targetsite T from the needle tube 184.

In such the procedure, the puncture needle 180 generally has largerbending stiffness as its outer diameter becomes larger. When the bendingstiffness is large, the expansion of the operation wire 98 and theshortening of the wire guide tube 99 are caused. Therefore, as comparedwith a case where the treatment tool is not led out from the treatmenttool exit part 58, sometimes, there may be a case where the angularposition θ2 of the forceps elevator 60 becomes small with respect to theangular position θ1 of the erecting operation lever 74. Here, even in acase where the angular position θ2 of the forceps elevator 60 withrespect to the angular position θ1 of the erecting operation lever 74 isinitially set to an angular position similar to a case where thetreatment tool is not led out from the treatment tool exit part 58,there may be a case where the angular position θ2 of the forcepselevator 60 gradually becomes smaller by the restoring force to restorethe puncture needle 180 to a straight shape.

In such a case, for example, when the erecting operation lever 74assumes only the above-mentioned first operation range (see FIG. 10) asthe entire operation range, the erecting motion range of the forcepselevator 60 becomes small and cannot be erected up to the originalmaximum angular position θ2max.

On the other hand, as angular position θ2 of the forceps elevator 60becomes smaller, that is, as the lead-out angle of the puncture needle180 becomes smaller, a site which can be punctured by the punctureneedle 180 led out from the treatment tool exit part 58 becomes smallerin an observation site imaged in an ultrasonic image, and the site isrestricted in a position near the ultrasonic transducer 50. Therefore,when the erecting motion range of the forceps elevator 60 is small, in acase where the target site T is far from the wall surface S and so on,it may be difficult to adjust the position and direction, and so on, ofthe distal end part 34 such that the target site T is imaged in theultrasonic image and the puncture needle 180 is directed in a directionof the target site T. Therefore, to facilitate the adjustment of theposition and direction of the distal end part 34, it is desirable thatthe forceps elevator 60 be in a state where it can be erected up to themaximum angular position θ2max.

Especially, in a case where the forceps elevator 60 is erected to be inthe maximum angular position θ2max and is used, since the direction ofthe puncture needle 180 led out from the treatment tool exit part 58 canbe specified beforehand, a position through which the puncture needle180 (needle tube 184) passes on the ultrasonic image can be estimatedbeforehand without confirming the direction of the puncture needle 180imaged in the ultrasonic image or the like. Therefore, it is possible toadjust the position and direction and so on of the distal end part 34such that the target site T is located in the direction of the punctureneedle 180, only by confirming the position of the target site T imagedin the ultrasonic image without confirming the direction of the punctureneedle 180 imaged in the ultrasonic image or the like. Moreover, thefine control of the angular position θ2 of the forceps elevator 60 canbe made unnecessary, and the operation of the forceps elevator 60 can befacilitated. Moreover, the same applies to a case where instrumentsother than the puncture needle 180 are used as a treatment tool.

In view of this, the erecting operation lever 74 of the presentembodiment has: the first operation range in which the operation wire 98is pulled within the erecting motion range of the forceps elevator 60 ina state where a treatment tool is not led out from the distal end part34 as illustrated in FIG. 10; and the second operation range in whichthe operation wire is further pulled when the operation wire is operatedmore greatly beyond the first operation range.

FIG. 12 illustrates a relationship diagram between the operation rangeof the erecting operation lever 74 and the erecting motion range of theforceps elevator 60 in a state where a treatment tool having a largebending stiffness is led out from the distal end part 34 (treatment toolexit part 58).

According to this, when the erecting operation lever 74 is operatedtoward the erecting side to gradually increase the angular position θ1of the erecting operation lever 74 from the minimum angular positionθ1min, the forceps elevator 60 is gradually erected and the lead-outangle of the treatment tool gradually becomes larger together with theangular position θ2 of the forceps elevator 60. However, there is a casewhere no change is caused in the angular position θ2 of the forcepselevator 60 in a range in which the angular position θ1 of the erectingoperation lever 74 changes by a predetermined angle from the minimumangular position θ1min.

Further, when the angular position θ1 of the erecting operation lever 74becomes the angular position θ1 a that is a boundary between theabove-mentioned first operation range and the second operation range,the angular position θ2 of the forceps elevator 60 does not become themaximum angular position θ2max in the erecting motion range but becomesthe angular position θ2 a smaller than the maximum angular positionθ2max.

Therefore, in a case where the erecting operation lever 74 can beoperated only within the first operation range, the forceps elevator 60cannot be erected up to the maximum angular position θ2max and itserecting position is restricted up to the angular position θ2 a.

Meanwhile, since the erecting operation lever 74 has the secondoperation range on the erecting side with respect to the first operationrange as mentioned above, when the erecting operation lever 74 isfurther operated toward the erecting side so as to make the angularposition θ1 of the erecting operation lever 74 gradually larger from theangular position θ1 a, the forceps elevator 60 is further erected andthe lead-out angle of the treatment tool gradually becomes largertogether with the angular position θ2 of the forceps elevator 60.

Further, when the angular position θ1 of the erecting operation lever 74becomes a predetermined angular position θ1 b equal to or less than themaximum angular positional θ1max, the angular position θ2 of the forcepselevator 60 becomes the maximum angular position θ2max within theerecting motion range.

According to this, in a state where a treatment tool having a largebending stiffness is led out from the treatment tool exit part 58, evenwhen the forceps elevator 60 is not erected up to the maximum angularposition θ2max only within the first operation range of the erectingoperation lever 74, the forceps elevator 60 can be erected up to themaximum angular position θ2max in the erecting motion range by movingthe erecting operation lever 74 to the angular position θ1 b in thesecond operation range which is larger than the first operation range oran angular position larger than the angular position θ1 b.

Here, when a case where the use of the second operation range of theerecting operation lever 74 is necessary and a case where it isunnecessary are considered, from the viewpoint of operability, it ispreferable that the first operation range of the erecting operationlever 74 be 40% or more and 70% or less with respect to the entireoperation range, and it is more preferable that be 50% or more and 70%or less.

Next, a mode when an index is provided, the index for identifyingwhether the operation range of the erecting operation lever 74 (angularposition θ1) is in the minimum angular position θ1min and whether theoperation range is the first operation range or the second operationrange, is described in the endoscope 1 according to the embodimentillustrated in above-mentioned FIGS. 1 to 12.

FIG. 13 is an expanded diagram illustrating a part which is arrangedopposite to the finger hook part 158 of the erecting operation lever 74in the lower surface 13D of the operation part 12 (casing 13). Here, thefinger hook part 158 is expressed by an alternate long and short dashline.

As illustrated in the figure, an index 200 having a color different fromthat of the lower surface 13D is provided to the lower surface 13D ofthe operation part 12. For example, the index 200 may be the one whichis directly recorded in the lower surface 13D by paint, and so on, ormay be a board member fixed to the lower surface 13D. Any device isacceptable as a device which provides the index to the lower surface13D.

Moreover, the index 200 has a long shape along the direction from theproximal end side to the distal end side of the operation part 12(back-and-forth direction) which is the movement direction of theerecting operation lever 74, and includes a small width part 200 ahaving a small width on the proximal end side and a large width part 200b having a large width on the distal end side.

This index 200 is provided in a position shielded by the finger hookpart 158 of the erecting operation lever 74 in a state where theerecting operation lever 74 is set to the proximal end position (minimumangular position θ1min) in the entire operation range illustrated inPart (A) of the figure. Here, a state where the erecting operation lever74 is set to the proximal end position corresponds to a state where theforceps elevator 60 is set to the minimum angular position θ2min in theerecting motion range as mentioned above.

Further, a proximal end 200 e of the small width part 200 a in the index200 is disposed in a position which substantially matches (substantiallymatches in the back-and-forth direction) with a proximal end 158 e ofthe finger hook part 158 of the erecting operation lever 74 in thestate.

Therefore, when the erecting operation lever 74 is operated toward theerecting side to set to an angular position on the distal end side withrespect to the proximal end position, and the forceps elevator 60 is setto a state where it is erected from the minimum angular position θ2min,the small width part 200 a in the index 200 is exposed and can bevisually checked by an operator.

Moreover, a proximal end 200 m of the large width part 200 b in theindex 200 is disposed in a position which substantially matches(substantially matches in the back-and-forth direction) with theproximal end 158 e of the finger hook part 158 in a state where theerecting operation lever 74 is set to the angular position θ1 a that isthe boundary between the first operation range and the second operationrange as illustrated in Part (B) of the figure.

Therefore, when the erecting operation lever 74 is greatly operatedtoward the erecting side beyond the first operation range and theangular position θ1 of the erecting operation lever 74 is an angularposition in the second operation range which is larger than the angularposition θ1 a, the large width part 200 b in the index 200 is exposedand can be visually checked by the operator. Here, the erectingoperation lever 74 in Part (C) of the figure shows the one when theangular position θ1 becomes the maximum angular position θ1max.

According to this, whether the angular position θ1 of the erectingoperation lever 74 is the minimum angular position θ1min can be knowndepending on whether the small width part 200 a of the index 200 isexposed, that is, whether the small width part 200 a is visuallychecked. And whether the forceps elevator 60 is erected from the minimumangular position θ2min can be known.

By this means, whether the forceps elevator 60 is in a reclined statecan be easily known by the operator at the time of insertion and removalof the insertion part 10 into and from the body inside, and it ispossible to prevent the insertion and removal operation of the insertionpart 10 and the bending operation of the bending part 32 in a statewhere the forceps elevator 60 is erected. Moreover, since what isrequired is only to make the index 200 to the operation part 12, it canbe simply realized at a low price.

Moreover, the operator can know whether the erecting operation lever 74moves to the second operation range, based on whether the large widthpart 200 b in the index 200 is exposed, that is, whether the large widthpart 200 b is visually checked. Moreover, it is possible to know whetherthe forceps elevator 60 is set to the maximum angular position θ2max ina state where a treatment tool is not led out from the distal end part34 (treatment tool exit part 58) or in a state where a treatment tool ofsmall bending stiffness is led out.

As mentioned above, the index 200 of the embodiment illustrated in FIG.13 is one example, and other modes are possible as long as it ispossible to identify whether the angular position θ1 of the erectingoperation lever 74 is the minimum angular position θ1min and whether itis in the first operation range or in the second operation range.

For example, the whole of the index 200 may not be shielded by theerecting operation lever 74 in a state where the erecting operationlever 74 is set to the minimum angular position θ1min, instead, only thedistal end side may be exposed. Moreover, the width level relationshipbetween the small width part 200 a and the large width part 200 b may bereverse. Different modes (colors and patterns, and so on) with the samewidth or different widths are acceptable.

Moreover, as illustrated in FIG. 14, the index may include an index 202and an index 204 which are configured by leaving only the proximal endpart of the small width part 200 a and the proximal end part of thelarge width part 200 b in the index 200 in FIG. 13. The index 202 andthe index 204 may have the same width.

Moreover, it may be designed such that the index can identify only anyone of whether angular position θ1 of the erecting operation lever 74 isthe minimum angular position θ1min and whether it is in the firstoperation range or in the second operation range. The index 200 in FIG.13 may be formed with only any one of the small width part 200 a and thelarge width part 200 b. Moreover, the index in FIG. 14 may include onlyany one of the index 202 and the index 204.

In addition, even in a case where the erecting operation lever 74 doesnot have the second operation range and has only the first operationrange, it is effective to provide with an index which shows whether theangular position θ1 of the erecting operation lever 74 is the minimumangular position θ1min, in the same way as the above-mentionedembodiment.

Next, a mode is described where a locking mechanism (load generatingdevice) which locks the movement (rotation) of the erecting operationlever 74 when the erecting operation lever 74 is operated in the secondoperation range, in the endoscope 1 of the embodiment illustrated inabove-mentioned FIGS. 1 to 12 or in the endoscope 1 of the embodimentswhich have the indices illustrated in above-mentioned FIGS. 13 and 14.

FIG. 15 is a diagram illustrating the erecting operation lever 74, thecoupling member 156, the rotating drum 154 and the fixing shaft 152 inthe operation-part power transmission mechanism 90 in FIG. 7, and FIG.16 is an expanded perspective view illustrating the locking mechanismprovided in the operation-part power transmission mechanism 90.

As illustrated in these figures, there provided is the locking mechanism210 which locks the movement of the erecting operation lever 74 when theerecting operation lever 74 is operated in the second operation range,between the rotating drum 154 which rotates around the axis 150 xtogether with the rotation operation of the erecting operation lever 74and the fixing shaft 152 fixed to the casing 13 by the support part 13b.

The locking mechanism 210 includes: a fixed part 212 which is providedin the operation part 12 (casing 13) by being fixed to the fixing shaft152; and a movable part 214 which is provided integrally with theerecting operation lever 74 by being fixed to the rotating drum 154 andmoves relative to the fixed part 212.

The fixed part 212 includes a disc-shaped tubular member 213 having athrough hole 213 a in a central part thereof. The small diameter part152 b of the fixing shaft 152 is inserted into the through hole 213 aand the fixed part 212 is fixed to a stepped part 152 c that is acoupling part between the large diameter part 152 a and the smalldiameter part 152 b of the fixing shaft 152 by a screw and so on. Here,the central axis of the fixed part 212 is disposed on the same axis asthe axis 150 x.

Moreover, the fixed part 212 is provided with a locking pin 220 thatprojects from a flat plate surface 213 b toward the side of the movablepart 214, in an outer peripheral part as illustrated in FIG. 16. Thelocking pin 220 has a chevron shape along the circumferential directionaround the axis 150 x.

Meanwhile, the movable part 214 is formed by overlapping two long andthin tubular members 240 and 242 which can be elastically deformed asillustrated in FIG. 16, and both end parts of those tubular members 240and 242 are fixed to two convex parts 155 which project in the radialdirection from the end part on the proximal end side of the rotatingdrum 154 by a screw and so on. Further, the movable part 214 includingthose tubular members 240 and 242 is disposed in a position facing theouter peripheral part of the fixed part 212.

Moreover, in the tubular member 240 disposed on the side of the fixedpart 212 among the tubular members 240 and 242 a, a locking projection244 that projects on the side of the fixed part 212 from a flat platesurface 240 a is provided. The locking projection 244 has a chevronshape in the circumferential direction around the axis 150 x.

By this means, the tubular members 240 and 242 support the lockingprojection 244 as an elastic support member which is elasticallydeformable. Here, the movable part 214 may be composed of only onetubular member 240. In the following, explanation is given assuming thatthe movable part 214 is composed of only one tubular member 240.

The locking pin 220 of the fixed part 212 and the locking projection 244of the movable part 214, which are formed in this way, are disposed inpositions that intersect with a cylindrical surface having the samediameter with respect to the axis 150 x. The fixed part 212 and themovable part 214 are disposed with a distance in-between such that thelocking pin 220 and the locking projection 244 are brought into contactwith each other when the movable part 214 rotates around the axis 150 xtogether with the rotating drum 154 by the rotation operation of theerecting operation lever 74.

FIG. 17 is a diagram simply illustrating configurations of the fixedpart 212 and the movable part 214 along the circumferential direction (adirection around the axis 150 x) when they are exploded in a plane, andis a diagram illustrating a relationship with the angular position θ1 ofthe erecting operation lever 74.

First, the position of the locking projection 244 when the lockingprojection 244 of the movable part 214 (the center of the lockingprojection 244) is set to the position of rotation angle θ3 around theaxis 150 x is expressed as angular position θ3, and the position of thelocking pin 220 when the locking pin 220 of the fixed part 212 (thecenter of the locking pin 220) is arranged in the position of rotationangle θ4 around the axis 150 x is expressed as angular position θ4.Moreover, assuming that the rotation angle range in which the lockingprojection 244 is rotatable, that is, the movement range in which thelocking projection 244 is movable is referred to as the entire movementrange, the angular position θ3 of the locking projection 244 when theangular position θ1 of the erecting operation lever 74 is set to theminimum angular position θ1min in the entire operation range isexpressed by θ3min as the minimum angular position in the entiremovement range, and the angular position θ3 of the locking projection244 when the angular position θ1 of the erecting operation lever 74 isset to the maximum angular position θ1max in the entire operation rangeis expressed by θ3max (>θ3min) as the maximum angular position in theentire movement range.

At this time, the angular position θ3 of the locking projection 244becomes the minimum angular position θ3min in the entire movement rangewhen the angular position θ1 of the erecting operation lever 74 is theminimum angular position θ1min as illustrated in the figure. Moreover,the angular position θ1 of the erecting operation lever 74 becomes themaximum angular position θ3max in the entire movement range when theangular position θ1 of the erecting operation lever 74 is the maximumangular position θ1max.

Further, the locking projection 244 moves in a range from the minimumangular position θ3min to the maximum angular position θ3max in responseto the movement of the erecting operation lever 74 in a range from theminimum angular position θ1min to the maximum angular position θ1max.

Meanwhile, the locking pin 220 is, at least, arranged within the rangeof the angular position θ3 of the locking projection 244 when theangular position θ1 of the erecting operation lever 74 is set to thesecond operation range. That is, if the angular position θ3 of thelocking projection 244 is assumed as θ3 a when the erecting operationlever 74 is in the angular position θ1 a that is the boundary betweenthe first operation range and the second operation range, the lockingpin 220 is arranged in a position where the angular position θ4corresponds to the angular position θ3 b which is, at least, the angularposition θ3 a or more and the angular position θ3max or less.

Here, the figure does not mean that the locking projection 244 is set ina position of the same rotation angle in the direction around the axis150 x as the erecting operation lever 74. The relative positionalrelationship between the locking projection 244 and the erectingoperation lever 74 is not limited to the specific one.

According to such arrangement of the locking projection 244 and thelocking pin 220, when the erecting operation lever 74 is operated fromthe minimum angular position θ1min toward the erecting side to make theangular position θ1 of the erecting operation lever 74 larger, thelocking projection 244 also moves toward the erecting side and theangular position θ3 of the locking projection 244 gradually becomeslarger from the minimum angular position θ3min. Here, the erecting siderelated to the locking projection 244 denotes a direction to erect theforceps elevator 60 in the movement direction of the movable part 214(locking projection 244) relative to the fixed part 212 (locking pin220), and the reclining side denotes a direction to recline the forcepselevator 60.

Further, when the erecting operation lever 74 moves to the secondoperation range and the locking projection 244 moves to the angularposition θ3 b, a slope surface 224 u on the erecting side of the lockingprojection 244 abuts on a slope surface 220 d on the reclining side ofthe locking pin 220 and they are engaged with each other. By this means,the locking projection 244 and the locking pin 220 are engaged with eachother on the reclining side, and a load is applied to the movement ofthe locking projection 244 toward the erecting side so that the movementof the erecting operation lever 74 toward the erecting side is locked.

Here, the engagement between the locking projection 244 and the lockingpin 220 on the reclining side means an engagement when a slope surface244 u on the erecting side of the locking projection 244 abuts on theslope surface 220 d on the reclining side of the locking pin 220, thatis, when the locking projection 244 is on the reclining side relative tothe locking pin 220. On the contrary, the engagement on the erectingside means an engagement when a slope surface 244 d on the recliningside of the locking projection 244 abuts on a slope surface 220 u on theerecting side of the locking pin 220, that is, when the lockingprojection 244 is on the erecting side relative to the locking pin 220.

Here, when an amount of force equal to or greater than a certain levelis applied to the locking projection 244 (movable part 214) toward theerecting side to release the engagement by an operator's operation ofthe erecting operation lever 74, the tubular member 240 that supportsthe locking projection 244 is elastically deformed and the lockingprojection 244 rides across the locking pin 220. By this means, theengagement between the locking projection 244 and the locking pin 220 onthe reclining side is released.

Moreover, in the following, the description that engagement is releasedmeans that: the locking projection 244 rides across the locking pin 220by the movement of the locking projection 244 toward the erecting sidein the case of engagement on the reclining side; and the lockingprojection 244 rides across the locking pin 220 by the movement of thelocking projection 244 toward the reclining side in the case ofengagement on the erecting side.

After the engagement between the locking projection 244 and the lockingpin 220 on the reclining side is released, when the erecting operationlever 74 is further operated toward the erecting side and the lockingprojection 244 moves toward the erecting side, the angular position θ3of the locking projection 244 becomes larger from angular position θ3 b.Then, when the erecting operation lever 74 becomes the maximum angularposition θ1max, the angular position θ3 of the locking projection 244becomes the angular position θ3max.

Meanwhile, after engagement between the locking projection 244 and thelocking pin 220 on the reclining side is released, in the angularposition θ1 c (see FIG. 17) of the erecting operation lever 74 when theslope surface 244 d on the reclining side of the locking projection 244abuts on the slope surface 220 u on the erecting side of the locking pin220, the locking projection 244 and the locking pin 220 are engaged witheach other on the erecting side and a load is applied to the movement ofthe locking projection 244 toward the reclining side. Thus, the movementof the erecting operation lever 74 toward the reclining side is locked.

Here, in a case where the locking projection 244 and the locking pin 220are engaged with each other on the erecting side and in a case wherethey are engaged on the reclining side, the angular position θ3 of thelocking projection 244 and the angular positions θ1 of the erectingoperation lever 74 are exactly different between those cases. However,since the difference is small, in the following, when the lockingprojection 244 and the locking pin 220 are engaged with each other, evenin either of engagement on the erecting side or on the reclining side,the angular position of the locking projection 244 at the time ofengagement is assumed as the angular position of the locking pin 220,and the angular position of the erecting operation lever 74 at the timeof engagement is assumed as the angular position of the erectingoperation lever 74 corresponding to the angular position of the lockingprojection 244 at the time of the engagement.

In a case where the locking projection 244 and the locking pin 220 areengaged with each other on the erecting side, when an amount of forceequal to or greater than a certain level is applied to the lockingprojection 244 (movable part 214) toward the reclining side to releasethe engagement by an operator's operation of the erecting operationlever 74, that is, when a force having an amount equal to or greaterthan an required amount to release the engagement between the lockingprojection 244 and the locking pin 220 on the erecting side is appliedto the movement of the locking projection 244 toward the reclining side,the engagement between the locking projection 244 and the locking pin220 on the erecting side is released in the same way as theabove-mentioned case. Then, when the erecting operation lever 74 isfurther operated toward the reclining side, the locking projection 244moves toward the reclining side together with the erecting operationlever 74. When the erecting operation lever 74 reaches the minimumangular position θ1min, the angular position θ3 of the lockingprojection 244 becomes the minimum angular position θ3min.

By the way, in a case where a treatment tool is led out from the distalend part 34 (treatment tool exit part 58), the restoring force torestore the treatment tool to a straight shape is applied to the forcepselevator 60, and the force toward the reclining side is applied to themovable part 214 through the operation wire 98, the slider 96 and therotating drum 154. Meanwhile, the system is configured such that theengagement between the locking projection 244 and the locking pin 220 onthe erecting side cannot be easily released by the amount of forceapplied from the treatment tool in such a way.

Therefore, when the erecting operation lever 74 is operated toward theerecting side and, in the second operation range, the locking projection244 is moved toward the erecting side beyond the angular position θ3 bin which the locking projection 244 and the locking pin 220 are engagedwith each other, even if an operator releases fingers from the erectingoperation lever 74 or does not hold the position of the erectingoperation lever 74 by large holding force, it is possible to lock theerecting operation lever 74 in a position when the locking projection244 and the locking pin 220 are engaged on the erecting side, and theangular position of the forceps elevator 60 and the lead-out angle ofthe treatment tool can be maintained.

Especially, as illustrated in FIGS. 32 and 33, when the erectingoperation lever 74 is operated by the thumb of the left hand and theforceps elevator 60 is erected up to the maximum angular position θ2maxin a case where the bending stiffness of the treatment tool is large, itis necessary to greatly bend the joint of the thumb so as to operate theerecting operation lever 74 to the second operation range as illustratedin FIG. 33. Further, in a case where the locking mechanism 210 does notexist, since it is necessary to keep applying the force toward theerecting side to the erecting operation lever 74 against the restoringforce to restore the treatment tool to a straight shape, it burdens onthe finger. However, by engaging the locking projection 244 and thelocking pin 220 with each other on the erecting side using the lockingmechanism 210 of the present embodiment, the operator can release thethumb from the erecting operation lever 74 or does not have to keepapplying a large force to the erecting operation lever 74 and anoperation load is mitigated.

Subsequently, a setup position of the locking pin 220 of the fixed part212 is described. FIG. 17 shows that the setup position of the lockingpin 220 may be an arbitrary angular position θ3 b that falls within anangular position range in which the locking projection 244 of themovable part 214 moves when the erecting operation lever 74 is operatedin the second operation range, that is, within the range from theangular position θ3 a to the angular position θ3max. Although the setupposition is not limited to a specific position, it may be arranged in acharacteristic angular position as follows.

FIG. 18 is a diagram illustrating configurations of the fixed part 212and the movable part 214 along the circumferential direction togetherwith a relationship with the angular position θ1 of the erectingoperation lever 74 in the same way as FIG. 17. The locking pin 220 inthe figure is arranged in an angular position which substantiallymatches the maximum angular position θ3max of the locking projection244. According to this, the locking projection 244 and the locking pin22 are engaged with each other on the erecting side when the erectingoperation lever 74 is operated to reach the maximum angular positionθ1max. Therefore, the movement of the erecting operation lever 74 towardthe reclining side can be locked in the maximum angular position θ1max.

Thus, by locking the erecting operation lever 74 in maximum angularposition θ1max, the forceps elevator 60 can be held in maximum angularposition θ2max (maximum erecting position) regardless of the degree ofthe bending stiffness of the treatment tool, except a case where thetreatment tool led out from the distal end part 34 is unexpected.

FIG. 19 is a diagram illustrating configurations of the fixed part 212and the movable part 214 along the circumferential direction togetherwith the relationship with the angular position θ1 of the erectingoperation lever 74 in the same way as FIG. 17.

The locking pin 220 in the figure is arranged in an angular positionwhich substantially matches the angular position θ3 a of the lockingprojection 244. The angular position θ3 a of the locking projection 244is an angular position of the locking projection 244 when the erectingoperation lever 74 is in the angular position θ1 a that is the boundarybetween the first operation range and the second operation range asmentioned above.

According to this, the locking projection 244 and the locking pin 22 areengaged with each other on the erecting side when the erecting operationlever 74 is operated to reach the angular position θ1 a that is theboundary between the first operation range and the second operationrange. Therefore, the movement of the erecting operation lever 74 towardthe reclining side can be locked in the angular position θ1 a.

Thus, by locking the erecting operation lever 74 in maximum angularposition θ1 a, if the degree of the bending stiffness of the treatmenttool led out from the distal end part 34 is normal, the forceps elevator60 can be held in the maximum angular position θ2max (maximum erectingposition).

Moreover, the locking projection 244 and the locking pin 220 are engagedwith each other on the reclining side before they are engaged on theerecting side, and, when an operator operates the erecting operationlever 74 to apply an amount of force equal to or greater than a certainlevel toward the erecting side to the locking projection 244, theengagement on the reclining side is released and they are engaged on theerecting side. Therefore, the operator can know that the operation ofthe erecting operation lever 74 shifts from the first operation range tothe second the operation range, from a rapid change in the amount offorce required for the operation of the erecting operation lever 74toward the erecting side.

As mentioned above, the fixed part 212 and the movable part 214 of thelocking mechanism 210 only have to include the locking pin 220 and thelocking projection 244 which are mutually engaged parts, or only have toinclude an elastic support member which supports the locking projection244 in addition to them. Other parts can be changed to have an arbitraryconfiguration. For example, the locking pin 220 may be formed not to bethe disc-shaped tubular member 213. The locking pin 220 may be formed tobe a tubular member having a size corresponding to only the periphery ina position where the locking pin 220 is arranged, and the tubular membermay be fixed to the stepped part 152 c of the fixing shaft 152.Moreover, the fixed part 212 may be fixed to an arbitrary material fixedto the casing 13 of the operation part 12 instead of the stepped part152 c of the fixing shaft 152, and the movable part 214 may be fixed toan arbitrary position of the rotating drum 154 or an arbitrary part ofan arbitrary member coupled with the erecting operation lever 74 insteadof the convex part 155 which projects in the radial direction from theend part on the proximal end side of the rotating drum 154. Moreover,the elastic support member which supports the locking projection 244 ofthe movable part 214 may be the one which supports the lockingprojection 244 by an arbitrary elastic member such as a spring, insteadof the tubular members 240 and 242 whose both ends are fixed such thattheir central parts are elastically deformable as mentioned above. And,the elastic support member may be the one whole of which faces a planeand is fixed to a member such as the rotating drum 154.

In addition, as a mode of the locking mechanism 210, a mode in which thefixed part 212 and the movable part 214 mutually adopt configurations ofthe other is acceptable. That is, regarding the locking mechanism 210including the fixed part 212 and the movable part 214 of arbitraryconfigurations, it is possible to adopt a mode of the locking mechanismin which the configuration of the fixed part 212 is used as aconfiguration of a movable part and the configuration of the movablepart 214 is used as a configuration of a fixed part.

These modifiable matters related to the fixed part 212 and the movablepart 214 of the locking mechanism 210 are applicable also in theembodiments shown below.

Next, modified examples of the above-mentioned locking mechanism 210 andits peripheral parts are described. In the following explanation, partsin which a modification is made to the above-mentioned embodiment aremainly described, and the same reference numerals as the above-mentionedembodiment are assigned to components of parts configured in the sameway as the above-mentioned embodiment, and the explanation is omitted.Moreover, the modified examples described below can be arbitrarilycombined and adopted.

First, a modified example of the movable part 214 of the lockingmechanism 210 is described.

In the locking mechanism 210 illustrated in FIGS. 15 to 19, the movementof the erecting operation lever 74 is locked by the engagement betweenthe convex parts of the locking pin 220 of the fixed part 212 and thelocking projection 244 of the movable part 214. However, the movement ofthe erecting operation lever 74 may be locked by engagement by frictionusing a friction plate as the movable part 214.

FIG. 20 is a diagram illustrating a configuration of the lockingmechanism 210 along the circumferential direction in that case. Asillustrated in the figure, the movable part 214 includes: a frictionplate 260; and a plate spring 262 which supports the friction plate 260.According to this, when the erecting operation lever 74 is operated inthe second operation range, the locking pin 220 of the fixed part 212slidingly contacts (is engaged) with the friction plate 260 as a slidingcontact member and is brought into pressure contact (pressinglycontacts) with the friction plate 260 by the plate spring 262 togenerate the friction force. Thus, the movement of the erectingoperation lever 74 is locked. Here, an arbitrary-shaped sliding contactmember which slidingly contacts with the friction plate 260 andgenerates the friction force can be used instead of the locking pin 220in this mode.

Next, a modified example of the fixed part 212 of the locking mechanism210 is described.

The fixed part 212 of the locking mechanism 210 illustrated in FIGS. 15to 19 has a configuration including one locking pin 220. However, as aconfiguration including multiple locking pins, the locking mechanism 21may be configured to lock the movement of the erecting operation lever74 in multiple positions when the erecting operation lever 74 isoperated in the second operation range.

FIG. 21 is a diagram illustrating a configuration of the lockingmechanism 210 in the circumferential direction in such the case, in thesame way as FIG. 17. As illustrated in the figure, the fixed part 212includes three locking pins 220 a, 220 b and 220 c respectively disposedin different angular positions θ4 a, θ4 b and θ4 c along the movementdirection of the movable part 214. In this configuration, when theerecting operation lever 74 is operated in the second operation range,if the locking projection 244 of the movable part 214 moves to any oneof the positions of the angular positions θ4 a, θ4 b and θ4 c, thelocking projection 244 is engaged with any one of the locking pins 220a, 220 b or 220 c. Accordingly, the movement of the erecting operationlever 74 is locked in three positions in the second operation range.Here, the number of locking pins included in the fixed part 212 may notbe three but may be two, four or more, and the angular positions inwhich multiple locking pins are placed may be equal intervals or may notbe at equal intervals.

Moreover, multiple locking pins in the fixed part 212 may not bediscretely disposed like the mode in FIG. 21, but locking pins 220 e maybe continuously disposed as illustrated in FIG. 22. In that case, thoselocking pins 220 e correspond to latch teeth 272 and can be formed witha latch board 270 as illustrated in FIG. 23. By this means, it ispossible to lock the movement of the erecting operation lever 74 incontinuous positions in the second operation range of the erectingoperation lever 74. Here, the latch teeth 272 may be disposed in a range(from angular position θ3 a to angular position θ3max) corresponding tothe whole of the second operation range or may be disposed in a partialrange.

In addition, the movement of the erecting operation lever 74 may besteplessly locked in the entire or partial range of the second operationrange of the erecting operation lever 74. FIG. 24 illustrates a mode ofthe fixed part 212 in that case. The fixed part 212 illustrated in thefigure includes: a friction plate 280 disposed along the movementdirection of the movable part 214; and a plate spring 282 which supportsthe friction plate 280. Further, when the erecting operation lever 74 isoperated in the second operation range, the locking projection 244 ofthe movable part 214 slidingly contacts with the friction plate 280 as asliding contact member and is brought into pressure contact with thefriction plate 280 by the plate spring 282 to generate the frictionforce. By this means, the movement of the erecting operation lever 74 islocked in continuous positions in the second operation range of theerecting operation lever 74. Here, in this mode, it is possible to usean arbitrary-shaped sliding contact member which slidingly contacts withthe friction plate 280 and generates the friction force, instead of thelocking projection 244. Moreover, the friction plate 280 may be disposedin a range (from angular position θ3 a to angular position θ3max)corresponding to the whole of the second operation range or may bedisposed in a partial range.

The fixed part 212 of the configurations illustrated in above-mentionedFIGS. 21 to 24 may not be provided only in a range (from angularposition θ3 a to angular position θ3max) corresponding to the secondoperation range of the erecting operation lever 74, but may be alsoprovided in the first operation range (from angular position θ3min toangular position θ3 a) of the erecting operation lever 74. Moreover,even in a mode in which the erecting operation lever 74 has only thefirst operation range, it is possible to provide the locking mechanismincluding the fixed part 212 having the configurations illustrated inFIGS. 21 to 24.

Next, explanation is given to a case where the locking mechanism 210 ofthe above-mentioned arbitrary embodiment is provided with a switchingmechanism which varies a relative distance between the fixed part 212and the movable part 214 to switch the fixed part 212 and the movablepart 214 between an engagement state and a non-engagement state.

First, a mode to move the movable part 214 by the operation of theerecting operation lever 74 and vary the relative distance between thefixed part 212 and the movable part 214 is described.

FIG. 25 illustrates the casing 13, the frame member 160, the erectingoperation lever 74, the coupling member 156, the rotating drum 154, thefixing shaft 152 and the frame member 160 in FIG. 7, and the fixed part212 and the movable part 214 of the locking mechanism 21 in FIG. 15. Asillustrated in the figure, two grooves 290 and 292 are formed along thecircumferential direction in the outer peripheral surface of therotating drum 154. Meanwhile, ball plungers 296 are fixed in multiplepositions in the inner peripheral surface of the annular frame member160 fixed to the casing 13. Each ball plunger 296 has a ball which isurged toward its tip end direction in the tip end part and a part ofwhich is exposed to the outside, and the ball exposed from the tip endpart of the ball plunger 296 is engaged with any one of two grooves 290and 292 of the rotating drum 154.

Moreover, the rotating drum 154 is supported so as to be movable in thedirection of the axis 150 x with respect to the fixing shaft 152, and issupported so as to be movable to a position in which the groove 290 isengaged with the ball plungers 296 and a position in which the groove292 is engaged with the ball plungers 296. Thus, when the relativedistance between the fixed part 212 and the movable part 214 of thelocking mechanism 210 varies and the groove 292 of the rotating drum 154is engaged with the ball plungers 296, the fixed part 212 and themovable part 214 of the locking mechanism 210 are engaged with eachother to be in an engagement state. When the groove 290 of the rotatingdrum 154 is engaged with the ball plungers 296, the fixed part 212 andthe movable part 214 of the locking mechanism 210 are not engaged witheach other to be in a non-engagement state. Here, the engagement statein which the fixed part 212 and the movable part 214 of the lockingmechanism 210 are engaged with each other and the non-engagement statein which they are not engaged mean, that, when the locking mechanism 210is formed with a locking pin (220) and a locking projection (244) likethe mode illustrated in FIG. 17, a state in which they are engaged (astate in which they can be engaged) and a state in which they are notengaged (a state in which they cannot be engaged). In a case where thelocking mechanism 210 is formed with a friction plate (260) and asliding contact member (locking pin 220) like the mode illustrated inFIG. 20, the engagement state and the non-engagement state mean that astate in which they slidingly contact with each other (a state in whichthey can slidingly contact with each other) and a state in which they donot slidingly contact with each other (a state in which they cannotslidingly contact with each other).

According to this, when the erecting operation lever 74 is operated torotate and so on in order to erect the forceps elevator 60, if theerecting operation lever 74 is pushed out toward the distal end side ofthe main shaft 150, it is possible to move the rotating drum 154 to aposition in which the groove 290 of the rotating drum 154 is engagedwith the ball plungers 296 as illustrated in FIG. 26, to make the fixedpart 212 and the movable part 214 of the locking mechanism 210 enter thenon-engagement state. Thus, even in a case where the movement of theerecting operation lever 74 is locked by the locking mechanism 210, itis possible to operate the erecting operation lever 74 without applyinga large amount of force. Moreover, it is possible to operate theerecting operation lever 74 without a load by the locking mechanism 210.

On the other hand, when the erecting operation lever 74 is pushed towardthe proximal end side of the main shaft 150, it is possible to move therotating drum 154 to a position in which the groove 292 of the rotatingdrum 154 is engaged with the ball plungers 296 like FIG. 25, and it ispossible to make the fixed part 212 and the movable part 214 of thelocking mechanism 210 enter the engagement state. Thus, it is possibleto lock the movement of the erecting operation lever 74 by the lockingmechanism 210.

Next, a mode in which the fixed part 212 is moved to vary the relativedistance between the fixed part 212 and the movable part 214 isdescribed.

FIG. 27 illustrates the erecting operation lever 74, the coupling member156, the rotating drum 154, the fixing shaft 152, and the fixed part 212and the movable part 214 of the locking mechanism 21 in FIG. 15. Asillustrated in the figure, the fixed part 212 of the locking mechanism210 is fixed to a support member 300. The support member 300 is acircular plate member having a through hole in its central part. Thefixing shaft 152 is inserted into the through hole and is disposed onthe same axis as the main shaft 150. Moreover, a switching lever 302 isextended to the support member 300, and the switching lever 302 extendsto the outside of an unillustrated casing (the above-mentioned casing13). The system is configured such that: when the switching lever 302 isoperated to move forward-and-backward along the axis 150 x or to rotatearound the axis 150 x, the support member 300 moves forward and backwardin a direction along the axis 150 x by an unillustrated mechanism so asto vary the relative distance between the fixed part 212 and the movablepart 214 of the locking mechanism 210. Thus, the fixed part 212 and themovable part 214 of the locking mechanism 210 can be switched betweenthe engagement state and the non-engagement state, by the operation ofthe switching lever 302.

According to this, even in a case where the movement of the erectingoperation lever 74 is locked by the locking mechanism 210, by making thefixed part 212 and the movable part 214 of the locking mechanism 210enter the non-engagement state by the operation of the switching lever302, it is possible to operate the erecting operation lever 74 withoutapplying a large amount of force. Moreover, it is possible to operatethe erecting operation lever 74 without a load applied by the lockingmechanism 210.

On the other hand, by making the fixed part 212 and the movable part 214of the locking mechanism 210 enter the engagement state by the operationof the switching lever 302, it is possible to lock the movement of theerecting operation lever 74 by the locking mechanism 210.

Next, the locking mechanism 210 of the above-mentioned arbitraryembodiment is described in a case where the amount of force (firstamount of force) for the movement of the movable part 214 (lockingprojection 244) toward the erecting side and the amount of force (secondamount of force) for the movement toward the reclining side are madedifferent.

First, a mode in a case where the first amount of force is made lessthan the second amount of force is described.

As illustrated in FIG. 17 or the like, it is assumed that the lockingmechanism 210 includes: the fixed part 212 having the chevron-shapedlocking pin 220 as the first projection; and the movable part 214 havingthe chevron-shaped locking projection 244 as the second projection.Moreover, it is assumed that the locking projection 244 (movable part214) includes: the slope surface 244 u on the erecting side as the firstsurface which presses the locking pin 220 when the forceps elevator 60is erected; and the slope surface 244 d on the reclining side as thesecond surface which presses the locking pin 220 when the forcepselevator 60 is reclined.

In such the mode, the locking projection 244 is formed into anasymmetrical chevron shape in which the slope angle of the slope surface244 u on the erecting side of the locking projection 244 (a slope anglewith respect to the movement direction of the locking projection 244) issmaller than that of the slope surface 244 d on the reclining side, asillustrated in FIG. 28. Thus, the locking projection 244 can easily rideacross (get over) the locking pin 220 by the movement toward theerecting side, as compared to a case when the locking projection 244rides across the locking pin 220 of the fixed part 212 by the movementtoward the reclining side.

That is, if the amount of force when the locking projection 244 ridesacross the locking pin 220 by the movement toward the erecting side isassumed as the first amount of force and the amount of force when thelocking projection 244 rides across the locking pin 220 by the movementtoward the reclining side is assumed as the second amount of force, thesecond amount of force becomes greater than the first amount of force.Here, the first amount of force can be paraphrased as the amount offorce required when the locking pin 220 rides across the slope surface244 u on the erecting side of the locking projection 244, and the secondamount of force can be paraphrased as the amount of force required whenthe locking pin 200 rides across the slope surface 244 d on thereclining side of the locking projection 244.

Moreover, if the amount of force applied to the erecting operation lever74 when the erecting operation lever 74 is operated in a direction inwhich the forceps elevator 60 is erected is assumed as the firstoperation amount of force and the amount of force applied to theerecting operation lever 74 when the erecting operation lever 74 isoperated in a direction in which the forceps elevator 60 is reclined isassumed as the second operation amount of force, by adopting the lockingmechanism 210 in this mode, the first operation amount of force becomesless than the second operation amount of force.

By contrast, in a case where the first amount of force is made greaterthan the second amount of force, the slope angle of the slope surface244 d on the reclining side of the locking projection 244 is smallerthan the slope surface 244 u on the erecting side as illustrated in FIG.29.

In this case, the second operation amount of force applied to theerecting operation lever 74 when the forceps elevator 60 is reclinedbecomes less than the first operation amount of force applied to theerecting operation lever 74 when the forceps elevator 60 is erected.

For example, in the case of the endoscope 1 including the ultrasonictransducer 50 of the present embodiment, for example, as illustrated inFIG. 11, the endoscope 1 is used when tissue sampling is performed bypuncturing target site T with the puncture needle 180. At this time, asthe puncture needle 180, there is a case where the one having a largebending stiffness is used. In that case, a large force is applied to themovement of the locking projection 244 toward the reclining side.Therefore, it is desirable to mitigate an operation load by increasingthe second amount of force for locking the movement of the erectingoperation lever 74 toward the reclining side against such the force anddecreasing the first amount of force for locking the movement of theerecting operation lever 74 toward the erecting side. That is, it isdesirable to make the second amount of force greater than the firstamount of force as illustrated in FIG. 28.

On the other hand, in an endoscope equipped with a side-view-typeendoscope observing device including an illuminating unit and anobserving unit in the distal end part of an insertion part likeduodenoscopy, in a case where a guide wire is used in the procedure ofERCP, it is considered that the locking to the movement of the erectingoperation lever 74 toward the reclining side by the above mentionedlocking mechanism 210 is used as a lock of the guide wire. In that case,when a position in which the guide wire is greatly bent by the forcepselevator 60 is assumed as a lock position, if a treatment tool having alow flexibility is used, there is a possibility that the treatment toolis damaged at the time when locked also in such the lock position.Therefore, in order to mitigate an operator's operation load, it isdesirable that: the first amount of force for locking the movement ofthe erecting operation lever 74 toward the erecting side is increased soas to notify the operator that the operation range enters the lockposition of the guide wire, that is, the range is not in a normaloperation range; and the second amount of force for locking the movementof the erecting operation lever 74 toward the reclining side isdecreased. That is, it is desirable to make the first amount of forcegreater than the second amount of force as illustrated in FIG. 29.

Here, FIGS. 28 and 29 illustrate only one locking pin 220 in the fixedpart 212, but it is possible to apply the mode illustrated in FIGS. 28and 29 even to a mode in which a plurality of locking pins 220 (lockingpin 220 e) are provided like the mode illustrated in FIGS. 21 and 22.

Moreover, these modes are effective even when a locking mechanismsimilar to the above-mentioned embodiment is applied to the firstoperation range in a case where the erecting operation lever 74 has onlythe first operation range.

Moreover, it is possible to adopt a configuration like FIG. 30, asanother mode of a locking mechanism in which the first amount of forceand the second amount of force are made different. In the lockingmechanism 210 in the figure, the movable part 214 has the chevron-shapedlocking projection 244 as the first projection, as illustrated in FIG.17 or the like.

Meanwhile, the fixed part 212 has a support member 312 in which aconcave part 312 a is formed, and a locking pin 310, as a secondprojection, is rotatably supported in the concave part 312 a by a shaft314.

The locking pin 310 is disposed such that a part of the lock pin 301projects from the concave part 312 a. In the part (projection part 310t) projecting from the concave part, there are formed: a first surface310 d which presses the locking projection 244 when the forceps elevator60 is erected (on which the slope surface 244 u on the erecting side ofthe locking projection 244 abuts); and a second surface 310 u whichpresses the locking projection 244 when the forceps elevator 60 isreclined (on which the slope surface 244 d on the reclining side of thelocking projection 244 abuts).

Moreover, the locking pin 310 is provided with a convex part 310 a. Theconvex part 310 a is urged to the anti-clockwise direction (a directionin which the projection part 310 t inclines toward the reclining side)centering on the shaft 314 by a spring 316 in the concave part 312 a inthe figure. Meanwhile, the convex part 310 a is inhibited from rotatingin the anti-clockwise direction in the figure by abutting on a lockingpart 312 b which is protrusively formed in (formed so as to protrudefrom) the opening part of the concave part 312 a.

Accordingly, when the movable part 214 moves toward the reclining sideas illustrated in the figure, the slope surface 244 d on the recliningside of the locking projection 244 abuts on the second surface 310 u onthe erecting side of the locking pin 310. At this time, the projectionpart 310 t of the locking pin 310 is pressed toward the reclining sideand the locking pin 310 is pressed toward the anti-clockwise directionin the figure. However, since the rotation in the anti-clockwisedirection is inhibited by the locking part 312 b, the rotation amount(second rotation amount) of the locking pin 310 at this time is small.

On the other hand, when the erecting operation lever 74 is operatedtoward the erecting side and the movable part 214 moves toward theerecting side, the slope surface 244 u on the erecting side of thelocking projection 244 abuts on the first surface 310 d on the recliningside of the locking pin 310 as illustrated in FIG. 31. Thus, theprojection part 310 t of the locking pin 310 is pressed toward theerecting side and the locking pin 310 is pressed toward the clockwisedirection in the figure. Since the rotation at this time is notprohibited by the locking part 312 b, the rotation amount of the lockingpin 310 (first rotation amount) becomes greater than the second rotationamount.

Therefore, the height of the locking pin 310 which the lockingprojection 244 rides across becomes smaller when the erecting operationlever 74 is operated toward the erecting side.

That is, if the amount of force when the locking projection 244 ridesacross the first surface 310 d on the reclining side of the locking pin310 by the movement toward the erecting side is assumed as the firstamount of force and the amount of force when the locking projection 244rides across the second surface 310 u on the erecting side of thelocking pin 310 by the movement toward the reclining side is assumed asthe second amount of force, the second amount of force becomes greaterthan the first amount of force.

In order to make the first amount of force greater than the secondamount of force by a configuration similar to FIGS. 30 and 31, it onlyhas to adopt a configuration in which the configuration of the fixedpart 212 in FIG. 30 is horizontally reversed (right-and-left reversed).

In the locking mechanism 210 illustrated in above-mentioned FIGS. 28 to31, the configuration can be modified so that the configuration of theprojection disposed in the fixed part 212 and the configuration of theprojection disposed in the movable part 214 are replaced with eachother. That is, it is possible to adopt a configuration in which any oneof the first projection and the second projection is disposed in thefixed part 212 and the other one is disposed in the movable part 214.

As mentioned above, the locking mechanism 210 of the above-mentionedembodiment is not restricted to an endoscope of a specific type, and itis applicable to an endoscope of an arbitrary type.

What is claimed is:
 1. An endoscope apparatus comprising: an insertionpart configured to be inserted into a body; an operation partcontinuously provided on a proximal end side of the insertion part; aforceps elevator which is erectably provided to a distal end part of theinsertion part, has an erecting motion range from a minimum angularposition to a maximum angular position, and is configured to guide atreatment tool led out from the distal end part; an operation wire whoseone end is coupled with the forceps elevator and which is inserted intothe insertion part; and an erecting operation member which is providedto the operation part, with which another end of the operation wire iscoupled, and which is configured to erect the forceps elevator bypulling the operation wire, wherein the operation part includes an indexwhich is shielded by the erecting operation member when the forcepselevator is in the minimum angular position, and which is exposed whenthe forceps elevator is in a position in which the forceps elevator iserected from the minimum angular position.
 2. The endoscope apparatusaccording to claim 1, wherein when a state in which the treatment toolis not led out from the distal end part is assumed, the erectingoperation member has: a first operation range in which the operationwire is pulled within the erecting motion range of the forceps elevator;and a second operation range in which the operation wire is furtherpulled when the erecting operation member is greatly pulled beyond thefirst operation range.
 3. The endoscope apparatus according to claim 2,wherein the operating part comprises a locking mechanism configured tolock a movement of the erecting operation member when the erectingoperation member is operated into the second operation range.
 4. Theendoscope apparatus according to claim 3, further comprising: a fixedpart provided in the operation part; and a movable part which isprovided integrally with the erecting operation member and is movablerelative to the fixed part, wherein the locking mechanism includes: alocking pin which is provided to one of the fixed part and the movablepart; and a locking projection which is provided to another one of thefixed part and the movable part, and supported by an elastic supportmember that is elastically deformable, and the locking mechanism locksmovement of the erecting operation member by engagement between thelocking pin and the locking projection when the erecting operationmember is operated into the second operation range.
 5. The endoscopeapparatus according to claim 1, further comprising a bending operationknob which is rotatably arranged to the operation part and is configuredto perform a bending operation of a bending part provided on a distalend side of the insertion part, wherein the erecting operation member isrotatably arranged on a same axis as a rotation axis of the bendingoperation knob.